1. Field of the Invention
The present invention relates generally to an apparatus and method for converting two-dimensional images into three-dimensional images.
2. Related Art
[1] There has been known a method for converting 2D images into 3D images, which method utilizes field memories for generating an image signal (hereinafter referred to as xe2x80x9cdelayed image signalxe2x80x9d) time-delayed relative to an original 2D image signal so as to output either one of the original 2D image signal and the delayed image signal as a left-eye image signal and the other as a right-eye image signal. Unfortunately, however, this method has a disadvantage of high costs because the field memories are necessary for generating the image signal time-delayed relative to the original 2D image signal. In addition, this method is adapted to convert only 2D motion images into 3D motion images.
It is, therefore, an object of the invention to provide an apparatus and method for converting the 2D images into the 3D images, which apparatus and method negate the need for the field memories for generating the image signal time-delayed relative to the original 2D image signal, thereby accomplishing the cost reduction.
It is another object of the invention to provide an apparatus and method for converting the 2D images into the 3D images, which apparatus and method are adapted to produce stereoscopic images even from the original 2D image signal representing still images.
[2] There has already been developed an apparatus for providing a stereoscopic image by committing a signal to display on a 3D display unit, the signal representing a 3D image composed of a left-eye image and a right-eye image having parallax therebetween. Furthermore, an apparatus for generating a 3D image signal from a 2D image signal has already been developed.
However, an apparatus has yet to be developed which is adapted to perform a real-time processing on the 3D image signal for adjustment of a stereoscopic effect of the 3D images produced from the 3D image signal.
It is, therefore, an object of the invention to provide an apparatus and method for performing the real-time processing on the 3D image signal for adjustment of the stereoscopic effect of the 3D images produced from the 3D image signal.
[3] There has been known a 2D/3D image converter which generates, from a 2D image, a first image signal used as a reference and a second image signal time-delayed relative to the first image signal and outputs either one of these image signals as the left-eye image signal and the other as the right-eye image signal thereby converting the 2D image into the 3D image.
As to the first image signal, the original 2D image signal is used as it is. A delay value of the second image signal relative to the first image signal depends upon a motion speed of an image represented the 2D image signal. The second image signal is generated in the following manner.
More specifically, a predetermined number of fields of the 2D image signal inputted in the 2D/3D image converter, which precede the current field, are stored in a plurality of field memories on a field-by-field basis. Then, out of the 2D image signals stored in the respective field memories, read out is a 2D image signal having a delay value determined based on the motion speed of the image represented by the 2D image signal. The 2D image signal read out from the field memory is the second image signal. The left-eye and right-eye image signals thus obtained are each changed in rate to twice the normal rate in order to prevent the occurrence of flickers when the left-eye and right-eye images are viewed through a time division shutter glasses.
FIG. 55 diagrammatically illustrates a construction of a prior-art 2D/3D image converter for generating a double-speed 3D image signal from the 2D image signal.
The 2D/3D image converter includes an integrated circuit (LSI) 1100 for converting the 2D image signal into the 3D image signal, a plurality of delay field memories 1200 connected to the integrated circuit 1100, and a doubling circuit 1300 for doubling frequencies of the left-eye and right-eye image signals outputted from the integrated circuit 1100.
FIG. 55 shows only components of the integrated circuit 1100 that are involved in the writing of data to and the reading of data from the delay field memories 1200. More specifically, the figure shows the components of the integrated circuit 1100, which include a write data path 1101, a write timing generating section 1102, a read data path 1103 and a read timing generating section 1104. Besides these components, the integrated circuit 1100 includes a motion vector sensing section, an interface connected to a CPU, and the like.
The write timing generating section 1102 and the read timing generating section 1104 are each supplied with a reference clock signal CLK generated based on a horizontal synchronizing signal HSYNC of the 2D image signal, a vertical synchronizing signal VSYNC of the 2D image signal, and a horizontal synchronizing signal HD generated based on the horizontal synchronizing signal Hsync as timed to the reference clock signal CLK. A frequency fCLK of the reference clock signal CLK is given by the following equation (1) with fH denoting a frequency of the horizontal synchronizing signal HD:
fCLK=910fHxe2x80x83xe2x80x83(1)
The integrated circuit (LSI) 1100 is supplied with a luminance signal (Y signal) and color difference signals (R-Y and B-Y signals) which three signals compose the 2D image signal. The integrated circuit 1100 outputs the right-eye and left-eye image signals having a relative time difference therebetween. The right-eye image signal is composed of a right-eye luminance signal Y(R) and right-eye color difference signals R-Y(R) and B-Y(R) whereas the left-eye image signal is composed of a left-eye luminance signal Y(L) and color difference signals R-Y(L) and B-Y(L).
Either one of the right-eye and left-eye image signals is generated from a signal of the 2D image signal inputted in the integrated circuit 1100, which signal is sent to the read data path 1103 via the write data path 1101. The other of the right-eye and left-eye image signals is generated from a signal of the 2D image signal inputted in the integrated circuit 1100, which signal is sent to the read data path 1103 via the write data path 1101 and the delay field memory 1200.
The Y, R-Y and B-Y signals inputted in the write data path 1101 are written to the field memories 1200 based on the reference signal CLK. Specifically, a clock frequency for writing to the delay field memories 1200 is equal to the frequency fCLK of the reference clock signal CLK.
The signals stored in the field memories 1200 are read out based on the reference clock signal CLK. That is, a clock frequency for reading from the delay field a memories 1200 is also equal to the frequency fCLK of the reference clock signal CLK.
Accordingly, the right-eye luminance signal Y(R) the right-eye color difference signals R-Y (R) and B-Y (R) the left-eye luminance signal Y (L), and the left-eye color difference signals R-Y (L) and B-Y (L), which are outputted from the integrated circuit 1100, each have the same horizontal and vertical frequencies with the horizontal and vertical frequencies of the 2D image signals.
The doubling circuit 1300 includes double-speed field memories 1301-1306 for respectively storing the right-eye luminance signal Y (R), the right-eye color difference signals R-Y (R) and B-Y (R), the left-eye luminance signal Y (L), and the left-eye color difference signals R-Y (L) and B-Y (L), which are outputted from the integrated circuit 1100; a double-speed field-memory write timing generating circuit 1307 for controlling the writing of data to these double-speed field memories 1301-1306, and a double-speed field-memory read timing generating circuit 1308 for controlling the reading of data from these double-speed field memories 1301-1306.
When the right-eye image signal is read out, the right-eye luminance signal Y (R) is read out from the double-speed field memory 1301, the right-eye color difference signal R-Y (R) is read out from the double-speed field memory 1302, and the right-eye color difference signal B-Y (R) is read out from the double-speed field memory 1303. When the left-eye image signal is read out, the left-eye luminance signal Y (L) is read out from the double-speed field memory 1304, the left-eye color difference signal R-Y (L) is read out from the double-speed field memory 1305 and the left-eye color difference signal B-Y (L) is read out from the double-speed field memory 1306.
The reference clock signal CLK is applied as the writing clock to the double-speed field memories 1301-1306 and the double-speed field-memory write timing generating circuit 1307. A clock signal CLKa with a frequency twice the frequency of the reference clock signal CLK is applied as the reading clock to the double-peed field memories 1301-1306 and the double-speed field-memory read timing generating circuit 1308.
As indicated by the following equation (2), a frequency fCLKa of the read clock signal CLKa is twice the frequency fCLK of the write clock signal CLK:
fCLK=2fCLKxe2x80x83xe2x80x83(2)
Thus, an image signal outputted from the doubling circuit 1300 has horizontal and vertical frequencies twice the horizontal and vertical frequencies of the 2D image signal.
FIG. 56 is a timing chart showing signals in respective parts of an arrangement wherein four delay field memories are provided and the left-eye image signal is delayed relative to the right-eye image signal by two fields.
The prior-art 2D/3D image converter requires the doubling circuit including the field memories for generating the double-speed 3D image signal, thus suffering high costs.
It is therefore, an object of the invention to provide a 2D/3D image converter which includes a reduced number of field memories from that of field memories in the prior-art image converter and hence, accomplishes the cost reduction.
A first apparatus for converting two-dimensional images into three-dimensional images according to the invention comprises characteristic value extracting means for extracting, from an inputted two-dimensional image signal, a perspective image characteristic value of each of plural parallax calculation regions defined in a one-field screen on a field-by-field basis; parallax information generating means for generating parallax information on each of predetermined unit areas in the one-field screen by using the image characteristic value extracted per parallax calculation region; and phase control means for generating a first image signal and a second image signal from a signal of the inputted two-dimensional image signal which resides in each predetermined unit area, the first and second image signals having a horizontal phase difference therebetween based on the parallax information related to the predetermined unit area.
For example, the parallax information generating means includes means for generating perspective image information per parallax calculation region by using the perspective image characteristic value of each parallax calculation region; and means for converting the perspective image information per parallax calculation region into parallax information per parallax calculation region.
For example, the parallax information generating means includes means for generating perspective image information per parallax calculation region by using the perspective image characteristic value of each parallax calculation region; means for correcting a perspective image information piece on a parallax calculation region which is included in a group of parallax calculation regions located vertically lower in screen (hereinafter referred to as xe2x80x9cvertical screen positionxe2x80x9d) than a parallax calculation region having a perspective image information piece indicative of the nearest perspective position and which has a perspective image information piece indicative of a perspective position a predetermined value or more farther from a perspective position indicated by a perspective image information piece on a parallax calculation region immediately thereabove, the perspective image information piece on the former parallax calculation region being corrected to indicate a perspective position closer to that indicated by the perspective image information piece on the latter parallax calculation region; and means for converting the corrected perspective image information piece on each parallax calculation region into a parallax information piece on each parallax calculation region.
For example, the parallax information generating means includes first means for dividing all the parallax calculation regions in the one-field screen into groups associated with respective objects included in the one-field screen by using the perspective image characteristic value of each parallax calculation region; second means for generating perspective image information per group by using grouping results given by the first means and the perspective image characteristic value of each parallax calculation region; third means for generating perspective image information per parallax calculation region by using the perspective image information per group; and fourth means for converting the perspective image information per parallax calculation region into parallax information per parallax calculation region.
The first means has the following features:
(1) The first means is adapted to divide all the regions in the one-field screen into groups based on a histogram showing a number of parallax calculation regions for each perspective characteristic value, each group including parallax calculation regions with perspective image characteristic values close to one another.
(2) The first means includes means for dividing all the regions in the one-field screen into groups based on a histogram showing a number of parallax calculation regions for each perspective image characteristic value, each group including parallax calculation regions with perspective image characteristic values close to one another; and means which, when a single group includes a plurality of regions spatially separated from each other, divides the spatially separated regions into different groups.
(3) The first means includes means for dividing all the regions in the one-field screen into groups based on a histogram showing a number of parallax calculation regions for each perspective image characteristic value, each group including parallax calculation regions with perspective image characteristic values close to one another; means which, when a single group includes a plurality of regions spatially separated from each other, divides the spatially separated regions into different groups; and means which, when there is a group including a predetermined number of parallax calculation regions or fewer, checks perspective image characteristic values of the parallax calculation regions of the group and parallax calculation regions adjacent to the group to determine whether or not to combine the group with any one of neighboring groups, and combines the group with the neighboring group when the group is determined to be combined therewith.
(4) The first means includes means for dividing all the regions of the one-field screen into groups based on a histogram showing a number of parallax calculation regions for each perspective image characteristic value, each group including parallax calculation regions with perspective image characteristic values close to one another; means which, when a single group includes a plurality of regions spatially separated from each other, divides the spatially separated regions into different groups; means which, when there is a group including a predetermined number of parallax calculation regions or fewer, checks perspective image characteristic values of the parallax calculation regions of the group and parallax calculation regions adjacent to the group to determine whether or not to combine the group with any one of neighboring groups, and combines the group with the neighboring group when the group is determined to be combined therewith; and means which checks perspective image characteristic values of parallax calculation regions of adjacent groups to determine whether to combine them together or not, and combines the two groups together when they are determined to be combined together.
For example, the second means is adapted to calculate the perspective image information on each group by using the perspective image characteristic value of each parallax calculation region of each group and a weighting factor previously defined for each parallax calculation region.
The third means has the following features:
(1) The third means includes means for correcting a perspective image information piece on a parallax calculation region which is included in a group of parallax calculation regions located vertically lower in screen than a parallax calculation region having a perspective image information piece indicative of the nearest perspective position and which has a perspective image information piece indicative of a perspective position a predetermined value or more farther from a perspective position indicated by a perspective image information piece on a parallax calculation region immediately thereabove, the perspective image information piece on the former parallax calculation region being corrected to indicate a closer perspective position to that indicated by the perspective image information piece on the latter parallax calculation region.
(2) The third means includes means for correcting a perspective image information piece on a parallax calculation region which is included in a group of parallax calculation regions located vertically lower in screen than a parallax calculation region having a perspective image information piece indicative of the nearest perspective position and which has a perspective image information piece indicative of a perspective position a predetermined value or more farther from a perspective position indicated by a perspective image information piece on a parallax calculation region immediately thereabove, the perspective image information piece on the former parallax calculation region being corrected to indicate a closer perspective position to that indicated by the perspective image information piece on the latter parallax calculation region; and means for correcting perspective image information pieces on respective pairs of parallax calculation regions included in adjacent groups and defining a boundary portion therebetween, thereby to limit a difference between the perspective image information pieces on the respective pairs within a predetermined range.
(3) The third means includes means for correcting a perspective image information piece on a parallax calculation region which is included in a group of parallax calculation regions located vertically lower in screen than a parallax calculation region having a perspective image information piece indicative of the nearest perspective position and which has a perspective image information piece indicative of a perspective position a predetermined value or more farther from a perspective position indicated by a perspective image information piece on a parallax calculation region immediately thereabove, the perspective image information piece on the former parallax calculation region being corrected to indicate a closer perspective position to that indicated by the perspective image information piece on the latter parallax calculation region; means for correcting perspective image information pieces on respective pairs of parallax calculation regions included in adjacent groups and defining a boundary portion therebetween thereby to limit a difference between the perspective image information pieces on the respective pairs within a predetermined range; and means for smoothing perspective image information pieces on parallax calculation regions of the same group thereby to limit a difference in the perspective image information pieces thereon within a predetermined range.
For example, the phase control means includes first storage means having a capacity to store the two-dimensional image signal representing up to the number of pixels included in one horizontal line and temporarily storing the two-dimensional image signal; second storage means having a capacity to store the two-dimensional image signal representing up to the number of pixels included in one horizontal line and temporarily storing the two-dimensional image signal; first read-address control means which controls a read address of the first storage means relatively to a standard read address decided based on a horizontal/vertical position of the inputted two-dimensional image signal according to the parallax information related to the predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the first image signal a horizontal phase of which leads from a reference horizontal phase defined by said standard read address by a value based on said parallax information; and second read-address control means which controls a read address of the second storage means relatively to said standard read address according to the parallax information related to the predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the second image signal a horizontal phase of which lags from the reference horizontal phase defined by said standard read address by a value based on said parallax information.
For example, the perspective image characteristic value is an optional one selected from the group consisting of luminance high-frequency component integration value, luminance contrast, luminance integration value, R-Y component integration value, B-Y component integration value and chrome integration value or an optional combination of the above. The luminance high-frequency component is meant to define high-frequency parts of frequency components of the luminance signal. The luminance contrast is meant to define intermediate-frequency parts of the frequency components of the luminance signal. The luminance integration value is meant to define a DC component of the frequency components of the luminance signal. The predetermined unit area is an area consisting of one pixel, for example.
A method for converting two-dimensional images into three-dimensional images comprising the steps of a first step of extracting, from an inputted two-dimensional image signal, a perspective image characteristic value of each of plural parallax calculation regions defined in a one-field screen on a field-by-field basis; a second step of generating parallax information on each of predetermined unit areas in the one-field screen by using the image characteristic value extracted per parallax calculation region; and a third step of generating a first image signal and a second image signal from a signal of the inputted two-dimensional image signal which resides in each predetermined unit area, the first and second image signals having a horizontal phase difference therebetween based on the parallax information related to the predetermined unit area.
For example, the second step includes a step of generating perspective image information on each parallax calculation region by using the perspective image characteristic value of each parallax calculation region; and a step of converting the perspective image information per parallax calculation region into parallax information per parallax calculation region.
For example, the second step includes a step of generating perspective image information on each parallax calculation region by using the perspective image characteristic value of each parallax calculation region; a step of correcting a perspective image information piece on a parallax calculation region which is included in a group of parallax calculation regions located vertically lower in screen than a parallax calculation region having a perspective image information piece indicative of the nearest perspective position and which has a perspective image information piece indicative of a perspective position a predetermined value or more farther from a perspective position indicated by a perspective image information piece on a parallax calculation region immediately thereabove, the perspective image information piece on the former parallax calculation region being corrected to indicate a closer perspective position to that indicated by the perspective image information piece on the latter parallax calculation region; and a step of converting the corrected perspective image information piece on each parallax calculation region into parallax information piece on each parallax calculation region.
For example, the third step includes a step of temporarily storing the inputted two-dimensional image signal in first storage means and second storage means, each storage means capable of storing the inputted two-dimensional image signal representing up to the number of pixels included in one horizontal line; a step of controlling a read address of the first storage means relatively to a standard read address decided based on a horizontal/vertical position of the inputted two-dimensional image signal according to parallax information related to a predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the first image signal a horizontal phase of which leads from a reference horizontal phase defined by said standard read address by a value based on said parallax information; and a step of controlling a read address of the second storage means relatively to said standard read address according to the parallax information related to the predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the second image signal a horizontal phase of which lags from the reference horizontal phase defined by said standard read address by a value based on said parallax information.
As the perspective image characteristic value, there is used an optional one selected from the group consisting of luminance high-frequency component integration value, luminance contrast, luminance integration value and chroma integration value or an optional combination of the above. Specifically, the luminance high-frequency component integration value may be used as the perspective image characteristic value. Otherwise, the luminance contrast may be used as the perspective image characteristic value. A combination of the luminance high-frequency component integration value and the luminance contrast may be used as the perspective image characteristic value. Alternatively, a combination of the luminance high-frequency component integration value, the luminance contrast and the luminance integration value may be used as the perspective image characteristic value. Further, a combination of the luminance high-frequency component integration value, the luminance contrast and the chroma integration value may be used as the perspective image characteristic value. Alternatively, a combination of the luminance high-frequency component integration value, the luminance contrast, the luminance integration value and the chroma integration value may be used as the perspective image characteristic value.
The predetermined unit area consists of one pixel, for example.
A second apparatus for converting two-dimensional images into three-dimensional images according to the invention comprises motion vector sensing means for sensing, from an inputted two-dimensional image signal, a motion vector of each of plural motion-vector detection regions defined in a one-field screen on a field-by-field basis; parallax information generating means for generating parallax information on each predetermined unit area in the one-field screen by using a horizontal component of the motion vector sensed per motion-vector detection region; and phase control means for generating a first image signal and a second image signal from a signal of the inputted two-dimensional image signal which resides in each predetermined unit area, the first and second image signals having a horizontal phase difference therebetween based on parallax information related to the predetermined unit area.
For example, the parallax information generating means is adapted to generate the parallax information per predetermined unit area of the one-field screen based on a horizontal component of the motion vector sensed per motion-vector detection region, a maximum horizontal component value, a motion vector detection region presenting the maximum horizontal component value, a minimum horizontal component value, a motion-vector detection region presenting the minimum horizontal component value, and information indicative of whether an image corresponding to each motion-vector detection region represents an object or a background.
For example, the phase control means includes first storage means having a capacity to store the inputted two-dimensional image signal representing up to the number of pixels included in one horizontal line and temporarily storing the inputted two-dimensional image signal; second storage means having a capacity to store the inputted two-dimensional image signal representing up to the number of pixels included in one horizontal line and temporarily storing the inputted two-dimensional image signal; first read-address control means which controls a read address of the first storage means relatively to a standard read address decided based on a horizontal/vertical position of the inputted two-dimensional image signal according to parallax information on a predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the first image signal a horizontal phase of which leads from a reference horizontal phase defined by said standard read address by a value based on said parallax information; and second read-address control means which controls a read address of the second storage means relatively to said standard read address according to the parallax information on the predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the second image signal a horizontal phase of which lags from the reference horizontal phase defined by said standard read address by a value based on said parallax information.
The predetermined unit area is an area consisting of one pixel, for example.
A second method for converting two-dimensional images into three-dimensional images according to the invention comprises the steps of a first step of sensing, from an inputted two-dimensional image signal, a motion vector of each of plural motion-vector detection regions defined in a one-field screen on a field-by-field basis; a second step of generating parallax information on each predetermined unit area in the one-field screen by using a horizontal component of the motion vector sensed per motion-vector detection region; and a third step of generating a first image signal and a second image signal from a signal of the inputted two-dimensional image signal which resides in each predetermined unit area, the first and second image signals having a horizontal phase difference therebetween based on parallax information related to the predetermined unit area.
In the second step, for example, the parallax information is generated per predetermined unit area of the one-field screen by using a horizontal component of the motion vector sensed per motion-vector detection region, a maximum horizontal component value, a motion-vector detection region presenting the maximum horizontal component value, a minimum horizontal component value, a motion-vector detection region presenting the minimum horizontal component value, and information indicative of whether an image corresponding to each motion-vector detection region represents an object or a background.
For example, the third step includes a step of temporarily storing the inputted two-dimensional image signal in first storage means and second storage means, each storage means having a capacity to store the inputted two-dimensional image signal representing up to the number of pixels included in one horizontal line; a step of controlling a read address of the first storage means relatively to a standard read address decided based on a horizontal/vertical position of the inputted two-dimensional image signal according to parallax information related to a predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the first image signal a horizontal phase of which leads from a reference horizontal phase defined by said standard read address by a value based on the parallax information; and a step of controlling a read address of the second storage means relatively to said standard read address according to the parallax information related to the predetermined unit area including the horizontal/vertical position of the inputted two-dimensional image signal, thereby generating the second image signal a horizontal phase of which lags from the reference horizontal phase defined by said standard read address by a value based on said parallax information.
The predetermined area consists of one pixel, for example.
A first stereoscopic effect adjusting method for adjusting a stereoscopic effect of a tree-dimensional image according to the invention is characterized by controlling a sharpness of an image contour per predetermined unit area of the three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image. The predetermined area consists of one pixel, for example.
More specifically, the sharpness of the image contour is controlled such that an area representing a near-view image is increased in the sharpness of the image contour while an area representing a distant-view image is decreased in the sharpness of the image contour. This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the sharper outline and the more distant object in the more blurred outline.
A second stereoscopic effect adjusting method for adjusting a stereoscopic effect of a three-dimensional image according to the invention is characterized by controlling a chroma per predetermined unit area of the three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image. The predetermined unit area consists of one pixel, for example.
More specifically, the chroma of the image is controlled such that an area representing a near-view image is increased in the image chroma while an area representing a distant-view image is decreased in the image chroma. This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the more vivid colors and the more distant object in the paler colors.
A third stereoscopic effect adjusting method for adjusting a stereoscopic effect of a three-dimensional image according to the invention is characterized by controlling a sharpness of an image contour and a chroma per predetermined unit area of the three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image. The predetermined unit area consists of one pixel, for example.
More specifically, the sharpness of the image contour is controlled such that an area representing a near-view image is increased in the sharpness of the image contour while an area representing a distant-view image is decreased in the sharpness of the image contour and that the area representing the near-view image is increased in the image chroma while the area representing the distant-view image is decreased in the image chroma. This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the sharper outline and the more vivid colors but the more distant object in the more blurred outline and the paler colors.
A first stereoscopic effect adjusting apparatus comprises image contour controlling means for controlling a sharpness of an image contour per predetermined unit area of a three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image. The predetermined unit area is an area consisting of one pixel, for example.
For example, the image contour controlling means is adapted to control the sharpness of image contour such that an area representing a near-view image is increased in the sharpness of image contour while an area representing a distant-view image is decreased in the sharpness of image contour. This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the sharper outline but the more distant object in the more blurred outline.
A specific example of the image contour controlling means is adapted to decrease a ratio of a low-frequency component and to increase a ratio of a high-frequency component of the three-dimensional image signal in an area representing a near-view image, and to increase a ratio of the low-frequency component and to decrease a ratio of the high-frequency component of the three-dimensional image signal in an area representing a distant-view image.
A second stereoscopic effect adjusting apparatus according to the invention comprises chroma controlling means for controlling a chroma of each predetermined unit area of a three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image. The predetermined unit area is an area consisting of one pixel, for example.
For example, the chroma controlling means is adapted to control the image chroma by increasing an image chroma of an area representing a near-view image and by decreasing an image chroma of an area representing a distant-view image. This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the more vivid colors but the more distant object in the paler colors.
A third stereoscopic effect adjusting apparatus according to the invention comprises image contour controlling means for controlling a sharpness of an image contour per predetermined unit area of a three-dimensional image according to perspective image information on each predetermined unit area of a one-field screen displaying the three-dimensional image; and chroma controlling means for controlling a chroma per predetermined unit area of the three-dimensional image according to the perspective image information on each predetermined unit area of the one-field screen displaying the three-dimensional image. The predetermined unit area is an area consisting of one pixel, for example.
For example, the image contour controlling means is adapted to control the sharpness of the image contour by increasing a sharpness of an image contour related to an area representing a near-view image and by decreasing a sharpness of an image contour related to an area representing a distant-view image, whereas the chroma controlling means is adapted to control the image chroma by increasing a chroma of the area representing the near-view image and by decreasing a chroma of the area representing the distant-view image.
This enhances the stereoscopic effect of the reproduced image because the human eye perceives the nearer object in the sharper outline and the more vivid colors but the more distant object in the more blurred outline and the paler colors.
For example, the image contour controlling means is adapted to decrease a ratio of a low-frequency component and increase a ratio of a high-frequency component of the three-dimensional image signal in an area representing a near-view image, and to increase a ratio of the low-frequency component and decrease a ratio of the high-frequency component of the three-dimensional image signal in an area representing a distant-view image.
A two-dimensional/three-dimensional image converter according to the invention comprises a plurality of field memories serving to store a predetermined number of fields of an inputted two-dimensional image signal which are earlier than the current field, and means for reading, from the plural field memories, respective pairs of image signals having a relative time difference therebetween and outputting one of the image signal pair as a left-eye image signal and the other as a right-eye image signal, the two-dimensional/three-dimensional image converter wherein a read clock for each field memory has a frequency set to twice the frequency of a write clock for the field memory.
Since the read clock for each field memory is set to twice the frequency of the write clock for the field memory, the left-eye image signal or the right-eye image signal read from each field memory has a horizontal frequency and a vertical frequency which are each twice the frequency of the two-dimensional image signal.